Q: Now that I’m single and dating again, I’m worried about catching genital herpes. How common is herpes, and how can I avoid it?

A: This incurable sexually transmitted disease is more common in women than in men because the vaginal area’s exposed mucous membranes are more vulnerable than the shaft of the penis. About one in four women and one in eight men in the US are infected with herpes simplex virus type 2 (HSV-2), the virus that causes most cases of genital herpes. The closely related herpes simplex virus type 1 (HSV-1), which causes oral herpes (“fever blisters”), is typically transmitted during childhood via nonsexual contact — but it also can cause herpes on the genitals if transmitted via oral sex. With either type of HSV, an infected person may have recurrent outbreaks of blistering ulcers on the genitals… or may never have symptoms and so be unaware of being infected.People with genital herpes can pass the virus to their sex partners any time there is contact between the mucous membranes of the mouth, throat, vagina or rectum… or when another part of the body is touched immediately after a herpes lesion has been touched. Though contagion is most likely during an active outbreak, infected people can spread HSV even when symptom-free.The only guaranteed way to avoid HSV is to abstain from sex — but since that is unrealistic, you need to know how to lower your risk. Before entering into a new sexual relationship, you and your potential partner should get blood tests to see whether you are already infected. If you both are infected with both HSV-1 and HSV-2, there is no additional herpes-related risk in having unprotected sex (though doing so during an outbreak could be painful for the affected person).If you are not infected but your partner is, understand that, even if you take precautions, there is still a significant risk of transmission. To lower that risk…

  • Consistently use a male or female condom for intercourse or a dental dam for oral sex. This reduces HSV transmission risk by one-third — but not by 100% because a condom may not cover all infected areas.
  • Your partner can take daily antiviral medication, such as valacyclovir (Valtrex), to reduce transmission risk and lower his susceptibility to outbreaks.
  • Abstain from sex whenever your partner has a visible lesion.